<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .div1{
            width: 100px;
            height: 100px;
            background: red;

            margin-bottom: 50px;
        }
        .div2{
            width: 100px;
            height: 100px;
            background: #2aff77;
            margin-top: 50px;
        }
    </style>
</head>
<body>

<!--  外边距合并:  在垂直方向上, 两个盒子模型的外边距紧相邻, 那么就会产生一种合并现象 -->

    <div class="div1">
        div1
    </div>
    <div class="div2">
        div2
    </div>

</body>
</html>
